Because wireless signals may be susceptible to interference from other wireless signals, may rapidly decline in strength with increased distance, and may be degraded by objects in the signal path that diminish or reflect the signals, errors in wireless communications are common. Various techniques have been developed to detect and correct wireless communications errors. Some techniques allow certain types of errors to be corrected at the receiver. However, many types of errors require that the data be retransmitted at a later time, thus extending the time it takes to successfully complete the communication. This delay in completion time may be detrimental if the communication is time-critical, i.e., if the data needs to be correctly received within a certain time period to avoid harmful consequences.
In some types of wireless communications protocols, multiple segments of data may be contained within a continuous transmission, and each of those segments may have a variable length that is specified by a field within the segment. For example, in the protocols defined in IEEE standard 802.16, multiple Protocol Data Units (PDUs) may be transmitted sequentially in a single burst transmission, with each PDU containing a length field that defines its length, so that a receiving device will know where in the transmission that the current PDU ends and the next PDU begins. Thus, if an error occurs in one PDU so that the end of that PDU cannot be reliably identified (e.g., if the Length field is corrupted), that PDU and all remaining PDUs in the transmission may have to be retransmitted. This may greatly increase the potential harm caused by the error, especially in time-critical communications.